Conventionally, in an air conditioner and the like, there is frequently used a cross fin and tube type heat exchanger provided with a large number of plate-shaped fins provided side by side in an air flow supplied by a fan, and a plurality of heat transfer tubes inserted into holes formed in the fins and arranged so as to be substantially orthogonal to the air flow direction.
In such a cross fin and tube type heat exchanger, in general, plural rows or plural columns of heat transfer tubes are arranged along the air flow direction. In order to enhance a heat exchanging performance between a refrigerant flowing in the heat transfer tubes and the ambient air, there are various proposals regarding outer diameters of the heat transfer tubes, a pitch of the fins, and the like (for example, refer to Patent Literatures 1 to 2).